Dissecting mechanisms of collective migration

PROJECT SUMMARY Background: Collective migration is a type of cell migrationwhere groups of cells move together in a coordinated fashion that is essential for development and disease progression, including wound healing or metastasis. During collective migration, a few cells at the front (i.e. leader cells) define the leading edge, integrate signals from the

surrounding environment and send signals to neighboring (follower) cells. Recent findings in our lab demonstrate in order for collective migration to occur, leader cells must first arrive (or polarize) at the front edge to begin the collective migration cascade. However, it is largely unknown how leader cells interpret signals from the

microenvironment via sensing of mechanical forces and how cell junction forces contribute to leader cell activation and collective migration. Thus, there is much interest to understand leader cell mechanotransduction and the signaling mechanisms used to drive collective migration. Hypothesis: Our central hypothesis is that dynamic extracellular matrix cues activate leader cell mechanics

via both cell-matrix and cell-cell contacts, are required to initiate and sustain directional collective migration. Goals: This project is divided into 3 main goals: 1. Investigate the effect of biomechanical cues to activate leader cells and directional collective migration 2. Elucidate which and how leader cell mechanics are

responsible for leader cell development, and 3. Investigate the functional role of forces at cell contacts and how cell junctional forces contribute to collective migration Study Design: We will combine microfluidic lab-on-a-chip devices which can modulate multiple microenvironment features, and investigate how mechanical cues effect leader cell development and

directional collective migration. We will also incorporate FRET-based tension sensors to our microfluidic platform so we can quantify changes in cell-cell load during leader cell driven collective migration in real-time. To understand how cell-matrix interactions effect leader cell development, we will measure matrix deformation

rate as exerted by leader cells on the surrounding environment. Furthermore, we will perform series of targeted knockdowns and rescue experiments to investigate our ability to disrupt, prevent, or revive collective migration by disrupting leader cell signaling. These studies will reveal how microenvironment cues, cell-matrix, and cell-

cell interactions contribute to leader cell development and mechanics that is essential for collective migration. Impact: Understanding the development of collective migration, and the role of leader cells in driving collective migration will pave the way for accelerated understanding of biological processes where collective migration is

fundamental to its success.